Question 1

An individual seaweed attached to the substratum is known as a&#10;A) Stipe&#10;B) Holdfast&#10;C) Thallus&#10;D) Blade

Accepted Answer

Thallus is the main body of the seaweed, which is attached to the substratum by the holdfast.

Question 2

Green seaweeds&#10;A) Are exclusively unicellular&#10;B) Use starch as their storage product&#10;C) Include the coralline algae&#10;D) Are exclusively multicellular

Accepted Answer

B

Question 3

Agar is extracted from a&#10;A) Red seaweed&#10;B) Bacterium&#10;C) Green seaweed&#10;D) Brown seaweed

Accepted Answer

Agar is extracted from red seaweed, specifically from the cell walls of certain species of red algae. It is widely used as a culture medium in microbiology and as a thickener and stabilizer in food products.

Question 4

Sea grasses differ from seaweeds in&#10;A) Having the ability to spread asexually&#10;B) Having chlorophyll&#10;C) Living on soft sediment&#10;D) Having flowers

Accepted Answer

Sea grasses are flowering plants (angiosperms) that live in marine environments, which distinguishes them from seaweeds (which are algae and do not have flowers). Seaweeds do not produce flowers, whereas sea grasses do, as part of their reproductive process.

Question 5

Benthic diatoms differ from their planktonic relatives in&#10;A) Being exclusively heterotrophic&#10;B) Living in chains of cells only&#10;C) Being usually bilaterally symmetrical&#10;D) Living only in estuaries

Accepted Answer

Benthic diatoms are often bilaterally symmetrical, which helps them live attached to surfaces or in sediments, contrasting with many planktonic diatoms that exhibit radial symmetry and float freely in water columns.

Question 6

Seagrasses&#10;A) Tend to live in waters deeper than kelps&#10;B) Are never found in the tropics&#10;C) Are very sensitive to low light conditions&#10;D) Live only in estuaries

Accepted Answer

Seagrasses are very sensitive to low light conditions, which is why they are typically found in clear, shallow waters where sunlight can easily penetrate. They rely on photosynthesis, so adequate light is crucial for their survival. Choices A, B, and D are incorrect because seagrasses can be found in a variety of marine environments, including both tropical and temperate regions, and not exclusively in estuaries or deeper waters than kelps.

Question 7

Cyanobacteria&#10;A) Only occur as single cells&#10;B) Are capable of nitrogen fixation&#10;C) Are closely related to fungi&#10;D) Are filamentous in shape, unlike the fungi

Accepted Answer

Cyanobacteria are capable of nitrogen fixation, which means they can convert atmospheric nitrogen into a form that is usable by living organisms. This is a key process in the nitrogen cycle and is not a capability of all bacteria. Cyanobacteria can exist as single cells or in colonies that form filaments, sheets, or hollow balls, not exclusively as single cells or filamentous shapes. They are not closely related to fungi; instead, they are a group of bacteria.

Deck 13: Benthic Microorganisms, Seaweeds, and Sea Grasses